Re: [opentcs-discuss] Using Database and OpenTCS

[<an...@sp...>]

Em 13/02/2018 12:47, Walter, Stefan escreveu:

> Hello André,
> 
> with "database", do you mean a relational (e.g. SQL) database?
> 
> Technically, you could use a database as the communication channel between your vehicle driver and the vehicle(s). However, I don't see how this would help in reducing resource usage. To connect to the DBMS, you would open a TCP connection as well, and reading from and writing to the database might even be more verbose than a simple protocol for directly communicating with your vehicle via a single TCP connection.
> 
> Here are some questions that would help understanding your situation:
> 
> - What exactly in your setup is consuming resources and slowing down your system?
> - Do you keep a single TCP connection open all the time, or do you open a new TCP connection for every message sent?
> - How are your messages encoded (binary, XML, ...)?
> - What size (number of bytes) are the messages exchanged?
> - With what frequency (messages per second) are these messages exchanged?
> 
> Best regards,
> Stefan
> 
> Von: an...@sp... [mailto:an...@sp...] 
> Gesendet: Freitag, 9. Februar 2018 20:36
> An: ope...@li...
> Betreff: [opentcs-discuss] Using Database and OpenTCS
> 
> Hello, I've developed my driver using a TCP/IP network to communicate with the vehicles. However, it became too slow and consumes too much processing resources from the vehicles and the server which runs OpenTCS.
> Once, the application is growing and more vehicles are intended to be added, we decided to move from the TCP/IP network to the use of a database, where OpenTCS would commit the informations and vehicles would query it from there.
> My doubt is whether it's possible and viable to implement the use of a database together with OpenTCS.
> 
> Thank you since now
> 
> Best regards
> 
> André
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Hello Stefan, 

Thank you for the attention, I have been thinking about using a
relational database (MySQL) to improve the performance, once the project
may have more than one AGV and we decided to try for a database because
we didn't want to be dependent on a single server that would host all
client connections. I will try to answer all your questions and hope you
can help me. 

 	* I believe that the connection is consuming the most part of the
resources, once no connection is setted, the resources go fine on their
operation.
 	* Yes, I do keep an open communication the whole time and only close
it when the vehicle disconnects (i.e: when it shutdows)
 	* I am using messages which are encoded using JSON and the messages do
not exceed more than 100 bytes.
 	* The messages are exchanged once OpenTCS releases a new '
MovementCommand ', so, it depends on the time the AGV reaches the
intended position (about 5 seconds or more)

Also, just to mention, the client is setted using python language, once
it runs on  a Raspberry PI3. 

Looking forward to your reply 

Best regards. 

André